The present disclosure relates to the micro devices.
Assuring reliability and yield are two critical tasks for the manufacturing of micro devices, such as integrated circuits and micro electromechanical systems (MEMS). Typically, in manufacturing micro devices, multiple micro devices are fabricated on a semiconductor wafer. The semiconductor wafer is then separated into individual dies each containing one or more individual micro devices. The electrical and optical performance of the micro devices are often tested for quality assurance on the individual dies in an ambient environment. For testing purposes, electrical and optical signals need to be properly input into the circuits in each micro device. Output electric and optical signals from the micro devices need to be properly detected and measured to analyze the functional performance of the micro devices. During testing and handling of the micro devices, the micro devices must not be contaminated by dust and pollutants in the ambient environment. Electrical and optical input and output, as well as protecting the micro devices from the environment, all need to be considered when designing packaging for the micro devices. Given the increased complexity of the micro devices and the testing requirements, a need exists for improved die packaging for the micro devices.
A common problem for MEMS is stiction between components that can contact each other during operations. For example, a micro mirror built on a substrate can include a tiltable mirror plate. The micro mirror can be driven by electrostatic forces to tilt about an axis. The mirror plate can tilt to two positions: an “on” position, wherein the micro mirror plate directs incident light to a display device, and an “off” position, wherein the micro mirror plate directs incident light away from the display device. The mirror plate can be stopped by mechanical stops at the “on” or the “off” positions so that the orientation of the mirror plate can be precisely defined at these two positions. For some micro mirror devices, the mirror plate stopped at the “on” or the “off” position must be able to overcome stiction between the mirror and the stop. A delay in the response of the mirror plate can be less than optimum in environments that require that the mirror respond quickly.